The present invention is related to core 1 xcex23-galactosyl transferases, polynucleotides which encode said core 1 xcex23-galactosyl transferases and methods of use thereof.
The core 1 O-linked glycan structure, consisting of galactose linked xcex23 to N-acetylgalactosamine linked to a threonine or serine on a protein, peptide or polypeptide, is a critical intermediate in the biosynthesis of most extended O-linked glycans (Glycoproteins and Human Disease (Brockhausen, I., and Kuhns, W., eds), (1997), pp. 13-31, R.G. Landes Company, Austin). The core 1 structure is found on a number of mucins and adhesion molecules. Core 1 xcex23-galactosyl transferase is the only enzyme which is capable of synthesizing the core 1 O-linked glycan structure Gal xcex23-GalNAc-Ser/Thr. Previous attempts to measure activity of core 1 xcex23-galactosyl transferase in vitro and to purify the enzyme have been made. However, previous attempts to sufficiently purify the protein to identify its amino acid sequence or generate antibodies to the enzyme, as well as attempts to identify cDNAs encoding the enzyme, have been unsuccessful. As a result, there has remained a need in the field for complete identification of core 1 xcex23-galactosyl transferase and of cDNAs encoding core 1 xcex23-galactosyl transferase.